Heretofore, it has been well known to clean the surface of an optical or laser-readable disc to eliminate distortion caused by foreign materials such as dust, smudges, oil, grease, dirt, hairs, fingerprints, or other similar substances which adhere to the protective coating or readable surface area of the laser disc. Such substances,distort the optical reading characteristics of the disc. It has also been known to provide systems or devices for buffing discs to remove scratches.
Laser discs were initially cleaned by hand with a cloth or brush and some type of cleaning solution. However, hand cleaning often resulted in uneven cleaning of the disc as well as distortion-producing scratch damage to the disc. Various mechanical disc-cleaning devices have been proposed to alleviate the problems which arise in hand cleaning laser discs. For example, various cleaning devices are disclosed in the following U.S. Pat. Nos. 4,520,470; 4,556,433; 4,561,142; 4,654,917; 4,662,025; 4,709,437; 4,713,856; 4,750,231; 4,783,870; 4,825,497; 4,854,001; 5,090,078; and 5,228,022.
While all of these patents emphasize the need for cleaning the disc surface, some of these patents state that scratches or marks on the disc surface are inconsequential. For instance, U.S. Pat. No. 4,654,917 explains that scratches on the surface of the disc do not affect the optical reading of information from the laser disc because the laser beam of a common reading device focuses below the surface of the disc. Other patents listed above stress the need to avoid circumferential scratches on the disc surface. For example, U.S. Pat. No. 4,561,142 explains that tangentially or concentrically oriented scratches may affect the reading of the disc, and U.S. Pat. No. 4,662,025 stresses the need to clean the laser disc in a radial direction such that any scratching of the laser disc will only be in the radial direction. Accordingly, at least some of the prior art recognizes the reading problem resulting from scratches or marks on a laser disc.
It has also been known to apply a scratch-removal substance to one or more scratches on the readable area of a disc, and thereafter hand-buff the area of the substance in a circular motion to ostensibly remove the scratch. This procedure requires prior identification of the scratch or scratches, and may result in not removing hard-to-see scratches. Further, the buffing action is not uniform with respect to the entire readable area.
The prior art generally uses parallel or nearly parallel cleaning elements to contact the disc for removing contaminants. While these devices may be satisfactory for the purpose of removing such contaminants from the surface of the disc, they are inadequate for applying the forces necessary for buffing the surface of the disc to remove scratches or marks from the entire laser-readable surface of the disc.
Consequently, although some of the prior art speaks in terms of cleaning the disc, scrubbing the disc, or hand buffing the disc in a radial fashion, the prior art does not show a compact device using a buffing wheel to engage and buff the disc at an angle substantially perpendicular to the disc and under substantial compression forces which removes marks or scratches from the disc by uniformly smoothing the entire surface of the disc.